肿瘤抗体药物偶联物的研发进展和挑战

抗体药物偶联物(antibody-drug conjugate,ADC)是通过连接子将抗体和小分子载荷药物进行连接,利用抗体作为载体将小分子载荷毒素靶向运输至目标细胞的新型药物。随着国内首款ADC药物维迪西妥单抗的上市,ADC药物的临床应用日益广泛。截至2022年2月,临床试验网站www.ClinicalTrial.gov显示有1685项注册临床试验正在开展。目前,全球共批准14款ADC药物上市,其中美国获批12款,日本和中国各1款。随着对ADC药物作用机制的理解加深和新药研发技术的不断突破,促使构成此类药物的抗体、载荷毒素、连接子及偶联技术均有飞速的发展。但是,ADC药物还存在诸多问题和挑战,如发展新型载荷毒素、降低异质性、保证均一性和稳定性等。为了更好地理解ADC药物的性质,本文就该类药物的技术进展进行综述。

Virtual population pharmacokinetic using physiologically based pharmacokinetic model for evaluating bioequivalence of oral lacidipine formulations in dogs

The aim of the present study was to investigate virtual population pharmacokinetic using physiologically based pharmacokinetic(PBPK) model for evaluating bioequivalence of oral lacidipine formulations in dogs. The dissolution behaviors of three lacidipine formulations including one commercial product and two self-made amorphous solid dispersions(ASDs)capsules were determined in 0.07% Tween 80 media. A randomized 3-period crossover design in 6 healthy beagle dogs after oral administration of the three formulations at a single dose of 4 mg was conducted. The PBPK modeling was utilized for the virtual bioequivalence study.In vitro dissolution experiment showed that the dissolution behaviors of lacidipine amorphous solid dispersions(ASDs) capsules, which was respectively prepared by HPMC-E5 or Soluplus, as polymer displayed similar curves compared with the reference formulation in 0.07% Tween 80 media. In vivo pharmacokinetics experiments showed that three formulations had comparable maximum plasma drug concentration(Cmax), and the time(Tmax) to reach Cmax of lacidipine tablet, which was prepared by Soluplus, as polymer was slower than other two formulations in consistency with the in vitro dissolution rate. The 90% confidence interval(CI) for the Cmax, AUC0–24 h and AUC0–∞ of the ratio of the test drug to the reference drug exceeded the acceptable bioequivalence(BE) limits(0.80–1.25). However, the 90% CI of the AUC0–24 h, AUC0–∞ and Cmax of the ratio of test to reference drug were within the BE limit,calculated using PBPK modeling when the virtual subjects reached 24 dogs. The results all demonstrated that virtual bioequivalence study can overcome the inequivalence caused by inter-subject variability of the 6 beagle dogs involved in in vivo experiments.

The studies of PLGA nanoparticles loading atorvastatin calcium for oral administration in vitro and in vivo

A biodegradable poly(lactic-co-glycolic acid) loading atorvastatin calcium(AC) nanoparticles(AC-PLGA-NPs) were prepared by probe ultrasonication and evaporation method aiming at improving the oral bioavailability of AC. The effects of experimental parameters, including stabilizer species, stabilizer concentration and pH of aqueous phase, on particle size were also evaluated. The resultant nanoparticles were in spherical shape with an average diameter of 174.7 nm and a narrow particle size distribution. And the drug loading and encapsulation efficiency were about 8% and 71%, respectively. The particle size and polydispersion were almost unchanged in 10 days. The release curves of AC-PLGA-NPs in vitro displaying sustained release characteristics indicated that its release mechanisms were matrix erosion and diffusion. The pharmacokinetic study in vivo revealed that the Cmax and AUC0-∞ of AC-PLGA-NPs in rats were nearly 3.7-fold and 4.7-fold higher than that of pure atorvastatin calcium suspension. Our results demonstrated that the delivery of AC-PLGANPs could be a promising approach for the oral delivery of AC for enhanced bioavailability.

Evaluation of pharmacokinetics underlies the collaborated usage of lamivudine and oxymatrine in beagle dogs

Combinational therapy of lamivudine and oxymatrine has been employed in the battle against hepatitis B virus in clinical setting. However, the pharmacokinetic behavior of the drug or active metabolism in intravenous/oral co-administration regime is poorly investigated. Herein,we evaluated the pharmacokinetic characteristic through a tailor-designed 3 way crossoverLatin square experiment in adult male beagle dogs. Six dogs were randomly treated by intravenous administration of lamivudine(2.5 mg/kg), oxymatrine(15 mg/kg) and combinational dosage, named as intravenous regime. Meanwhile the other six dogs were orally administrated with lamivudine(2.5 mg/kg), oxymatrine(15 mg/kg) and combinational dosage,named as oral regime. The pharmacokinetic feature in simultaneous oral treatment appeared to have no significant difference when compared with individual administration,even including matrine, the active metabolite of oxymatrine. In intravenous regime, the main pharmacokinetic parameters of simultaneous administration were nearly consistent with intravenous regime remedy. The collaborated application of lamivudine and oxymatrine contributed to non-distinctive pharmacokinetic fluctuations of beagle dogs in intravenous/oral regime, compared with individual employment, which established a vital base for the clinical co-administration against hepatitis B. Furthermore, the present study demonstrated that the determination of pharmacokinetics between combinational and individual therapy might assist in the development of drug compatibility in clinical therapy.

Development and evaluation of taste-masked dry suspension of cefuroxime axetil for enhancement of oral bioavailability

Cefuroxime axetil(CA)is an ester prodrug of cefuroxime with an unpleasant taste when administrated orally.This work was to mask the bitter taste of CA and enhance its oral bioavailability.Dry suspensions were prepared by means of wet granulation method and solid dispersion method.Binders,suspending agents and other compositions involved in the formulation were optimized.The differential scanning calorimetry(DSC)analysis indicated that CA was amorphous in the solid dispersion with stearic acid as the carrier,which contributed to an improvement of the dissolution rate.Taste evaluation was performed by three volunteers and taste masking was successfully achieved by the methods mentioned above.A pH 7.0 phosphate buffer was adopted to study the in vitro dissolution performance of the three formulations,i.e.,two self-made dry suspensions and the commercial one.With a better release characteristic and a satisfying taste masking ability,the solid dispersion suspension was selected as the optimal formulation for the further pharmacokinetic study in beagle dogs.The values of Cmax and AUC0e12 for the solid dispersion suspension were about 1.78-fold and 2.17-fold higher than these of reference suspension,respectively.The obtained results demonstrated that the solid dispersion can efficiently mask the bitter taste of CA and significantly enhance its oral bioavailability.

Degradation kinetic study of lysine in lysine hydrochloride solutions for injection by determining its main degradation product

A limited number of researches have been reported to apply the Arrhenius equation to study the relationship between drugs and its degradation products so far.In the present work,the thermal degradation kinetics of lysine hydrochloride solutions for injection,the special solvent for ademetionine 1,4-butanedisulfonate(SAM)for injection,was investigated at selected temperatures and pH values.The main degradation product of lysine was separated,purified,and confirmed as lysine lactam.A reversed-phase high performance liquid chromatographic(RP-HPLC)method without derivation was developed for the simultaneous determination of lysine and lysine lactam.The results confirmed that both the lysine degradation and lysine lactam generation followed zero-order reaction kinetics.The degradation and generation rate constants increased with increasing temperatures and decreasing pH values.The temperature-dependent degradation and generation reaction could be sufficiently modeled on the Arrhenius equation with the activation energy of 80.14 and 83.22 kJ/mol,respectively.Meanwhile,a linear relationship existed between the amount of lysine degradation and lysine lactam generation since the approximate activation energy.Considering there could be other side effects,we established an upper limit of lysine lactam(500 mg/ml),as the acceptable criteria for stability to estimate the shelf life together with lysine,which made the prediction more accurate and credible.Extrapolation data demonstrated that the lysine hydrochloride solutions for injection could be stable for two years stored at room temperature.